This invention relates to improvements in centrifugal cleaners and/or separators and in canister type installations thereof which render such devices economical to fabricate, more efficient and satisfactory in use, adaptable to a wide variety of applications and unlikely to malfunction. Such devices have a wide variety of application not the least of which is their important application to the processing of pulp. In such applications their use is to separate and classify the contents of a pulp slurry into accepts and rejects so that the pulp fibers which are eventually utilized in a paper making, board making or similar process will be clean and well defined and retain optimal strength for the purpose intended.
While the art in question has been highly advanced, it has far from reached a peak. The structure and concepts involved are so simple that the solution of problems encountered in its developing use has proven to be exceedingly difficult, particularly as related to the needs evidenced in the development of associated production techniques in related fields. Basic to the needs and solution of problems evidenced in the use of heretofore known centrifugal cleaners has been the necessity of finding a way to increase their throughput while maintaining and preferably increasing their cleaning efficiency. A lower pressure drop with increased throughput has also been a primary goal of researchers. That a solution to such a problem would be important, particularly in pulp processing, has been well recognized for some time since inherent in the solution would be an ability to achieve better results in a single pass through a centrifugal cleaner. Under such conditions not only would the processing of pulp be expedited but a given processing installation, for a given application and output, would require a smaller number of cleaners, thereby minimizing capital investment, installation and maintenance requirements and costs.
It is to the solution of the foregoing problem that the present invention has been successfully directed.
In addition to the foregoing, other problems have been evidenced in the application of multiple centrifugal cleaners or separators in canister type installations. In such installations, the form and nature of the conventional construction of centrifugal cleaners and/or separators has made them difficult and time consuming to install, particularly in a manner to achieve a compact package. Not only has set up time for a canister type installation been excessive but the nature of the packages so provided have presented plumbing difficulties and high cost in their maintenance. Even more important, prior art canister type installations have not been readily adaptable to a change of application. Such problems are also solved by the present invention.
As far as the present inventors are aware, the following patents are those most pertinent to the present invention:
______________________________________ U.S. 3,724,674 Loison April 3, 1973 3,105,044 Troland Sept. 24, 1963 2,719,631 Vicard Oct. 4, 1955 1,990,943 Horne et al Feb. 12, 1935 2,956,679 W. Hoffmann Oct. 18, 1960 3,598,731 R.H. Frykhult et al Aug. 10, 1971 3,717,255 Rowland et al Feb. 20, 1973 3,335,860 J. Baxter,Jr. Aug.15, 1967 3,543,931 Edward L. Raestatter Dec. 1, 1970 Canada 677,785 Freeman et al Jan. 14, 1964 588,344 Freeman et al Dec. 8, 1959 Norway 103,815 Voith Feb. 22, 1964 ______________________________________
While the noted patents flirt, to some extent, with the noted problems, they do not afford either the particularly advantageous solutions or the construction for centrifugal separators and/or cleaners and canister type installations thereof as achieved by the present invention.